def UARTResource(*args, rx, tx, rts=None, cts=None, dtr=None, dsr=None, dcd=None, ri=None,
conn=None, attrs=None, role=None):
- assert role in ("dce", "dte")
+ if any(line is not None for line in (rts, cts, dtr, dsr, dcd, ri)):
+ assert role in ("dce", "dte")
if role == "dte":
dce_to_dte = "i"
dte_to_dce = "o"